This is probably fine, but the only confusing thing to me is that https://github.com/dateutil/dateutil/tree/master/src/dateutil seems to show the code hasn't changed in 3 years.

This is probably fine, but the only confusing thing to me is that https://github.com/dateutil/dateutil/tree/master/src/dateutil seems to show the code hasn't changed in 3 years.

The specific issue is:

    def getzoneinfofile_stream():
        try:
            return BytesIO(get_data(__name__, ZONEFILENAME))
        except IOError as e:  # TODO  switch to FileNotFoundError?
>           warnings.warn("I/O error({0}): {1}".format(e.errno, e.strerror))
E           UserWarning: I/O error(2): No such file or directory

It's failing to open "dateutil-zoneinfo.tar.gz". My guess is that this is built via some script and pip install directly from the github repository doesn't include this file.

Apparently, you need to run "updatezinfo.py":
dateutil/dateutil#1395